Electric clock system



Jan. 29, 1935. A. F. POOLE 1,989,605

ELECTRIC CLOCK SYSTEM Filed July 50, 1932 2 Sheets-Sheet 1 INVENTOR Jan. 29, A. POOLE ELECTRIC CLOCK SYSTEM Filed July 30, 1932 2 Sheets-Sheet 2 INVENTOR Patented Jan.'29, 1935 ELECTRIC CLOCK SYSTEM Arthur F. Poole, Ithaca. N. Y.; Maryline B. Poole administratrix ceased of said Arthur F. Poole, de-

Application July so, 1932, Serial No. mg'zoa 7 Claims. (Cl. ass-s) My invention is an electric clock system whose object is to synchronize motor clocks shown in my Patent #1,31 0,372.of 1919.

During the last ten or twelve years so called 5- motor clocks constructed according to the teachings of my patent above referred to, have largely superseded other forms of clocks. Where regulated alternating current is available motor clocks form the cheapest and most accurate way of sup- .plying time. However these clocks have the disadvantage that the power to run them comes over the light mains, when this current is interrupted, called an outage, from an electrical storm, a blown fuse or circuit breaker, or any other cause the clocks stop and have to be set after the current is resumed. It is'one of the objects of my invention to provide a means of setting these motor clocks over the wires used to drive them to bring them thereby to the correct time. A further object of my invention is to provide a synchronizing mechanism which shall be responsive to a break in the regulated current. Another object of my invention is to so plan the synchronizing mech that it shall not respond to a single breakin the current but shall require a succession of breaks in a certain timed relation in order to prevent operation of the synchronizing mechanism from an accidental interruption of the line current. A further" object is to split up the clocks into groups and by a signal sent from the power house over the line wires to bring these groups into unison.

In alarge number of power distributions electricity may be supplied from several widely separated power houses, breaking all these sources of supply simultaneously may be inconvenient or impossible. To take care of synchronization in this case I have provided at one station a source of characteristic current, for instance a current of 1000 cycles per second, and at the synchronizing period this is impressed on the line. At each group of clocks is provided a detector and an amplifier, if the latter is required, the current from which actuates a relay which breaks the current to that group of clocks and thus synchronizes them. By this means it is possible for a single station to synchronize the clocks connec .d to an extensive network Another object of my invention is in the provision of two independent means of advancing the time indicating means of a timepiece, one of these means is by a synchronous motor run from regulated current and the other is controlled by a break in said current. Another object of my invention is the provision of novel synchronizing mechanism for the secondary clocks, said mechanism being responsive to repeated impulses which advance the hands to (or whatever point of synchronization may be selected). When the hands have reached 60 further impulses are ineffective to advance the hands of this particular clock. It is thus possible to bring the hands of all the clocks to 60 in spiteof the fact that they were not in unison when the start was made. A further object of nry invention'is synchronizing mechanism which will set the hands of the clocks back as well as forward.

The above and other objects of my invention will be set-forth in the following. specification and claims and willbe apparent to those skilled in the art from the following description.

My invention will be best understood by refer- I ence to the drawings of which:'F'ig. 1 is a more or less diagrammatic view of the parts of the secondary clock, these'parts being duplicated in each of the secondary clocks connected to'the system,- Fig. 2 is an alternative magnetic structure from' that shown in Fig. 1; Fig. 3 is a detail; Fig.1, a view showing some of the parts shown in Fig. l in an alternative position; Fig. 5 is a detail of the winding mechanism and Fig. 8 a circuit diagram of central stations, power distribution lines,-

substations and apparatus thereat and the master clock arrangements at one of the 'power stav tions to send the synchronizing current. Like figures of reference designate the sameparts inall the figures.

In describing my improved system I shall first describe the mechanism of the secondary clocks and for the sake of clearness, will show the synchronizing action as operated'from a manually operated switch. This would correspond to the case of a small group of secondary clocks in a single building which were synchronized manually from a time signal. a

After having described the mechanism of a single secondary clock I will then describe the organization of a system, in this case a characteristic current is impressed on the lines, at the various substations this characteristic current is detected and translated into a break in the lines carrying current to the secondary cl thus these clocks are synchronized.

Referring now to the drawings (Fig. 1) 10 and 11 are light and power mains supplied with regulated alternating current from the power house. A switch 12 in the circuit is for the purpose of setting the hands of the clocks in the group as afterwards described below. The switch 12 altho shown open, is normally closed and regulated A. C. is supplied to the winding 13 of a shelf starting synchronous motor 14 provided with an armature 15 and extra poles 16 and 17, said poles controlling the position of a second armature 18 pivoted in the framework at 19 and held against a spring 20 in contact with a stop 21 in the framework. When the current is cut of! from the winding 13 the spring 20 pulls the armature 18 in contact with a second stop 22 in the framework.

The armature 15 is connected by a train of reducing gearing 16', 1'7, 18', 19' and 20' to a center shaft 21' which carries a minute hand 23. The gear 20' is, connected to the shaft 21' by a frictional connection 22' which permits the setting of the hand 23 independent of the shaft 21. There is also provided an hour hand and usual motion work to run the hour hand at the proper ratio from the shaft 21' I have not shown these parts since they form no part of my present invention. Further I have not shown the reducing train between the motor 14 and the hand 23 in detail since such trains are well known in the art. Its function is to reduce the revolutions ofthe motor 14 to one revolution per hour. The parts so far described, except the armature 18 and its associated parts will be recognized as those of a synchronous motor clock. I will now describe the parts peculiar to my present invention.

Rigid on the center shaft 21 is a setting wheel 24 having teeth 26 at an angle of degrees with each other. One of the teeth 26 is cut out to determine a zero position of the wheel 24 and the hand 23 both of which are rigid with the shaft 21'. The wheel 24 is adapted to be driven in a clockwisedirectionby a spring pawl 27 mounted on a bar 28 turning .on'a pivot '29 on the end of an arm 30 which is rocked about a pivot 31 by means presently to be described. The bar 28 is guided during its travel by a pin 33 which constrains a slot 32 in said bar. As shown in Fig. 1 reciprocation of the-bar 28 will not result in feeding of the wheel 24 since the pawl 2"! is held out of engagement with the wheel 24 by the position of the pin 33. If, however, said pin is in the position shown in Fig.4 then repeated reciprocations of the bar 28 will result in feeding the wheel 24 step by step in a clockwise direction until pawl 27 reaches the position of the missing tooth 26 when further advance of the wheel 24 will stop, additional reciprocations of the bar 28 being-ineffective.

I will now describe the means for controlling the position of the pin 33. This pin is on a lever 34 pivoted in the framework at 35 and given a tendency to rotate in a clockwise direction by a spring 36 fastened to the framework at 3'7. This rotation is prevented by a detent 38 pivoted in the framework at 39 and held in contact with a stop 46 on the framework bya spring 41 between the detent 38 and the framework at 37. The detent 38 is provided with a tail 42' which is adapted to be engaged by a lever 43 mounted to rotate on a lever 44 at the pivot 45. The lever 44 is on a pivot 46 in the framework and is held by a spring 4'! in contact with a stop 48. A pull rod 49 joins the lever 43 with the armature 18..

the bar 28 to feed the wheel 24 it is required that the detent 38 be tripped, otherwise the bar 28 will make an idle' stroke. In'order for the detent 38 to be tripped two conditions must simultaneously be present; first, the current must be broken and second, the lever 43 must be in its raised position so that said lever will actuate the tail 42. When these two conditions are present, and only then, the reciprocation of the bar 28 will feed the wheel 24.

To reciprocate the bar 28 I have provided a power train consisting of the barrel 50 in which is frictionally mounted a spring 51. The barrel 50 is mounted ona shaft 52 to which the center 'of the spring 51 is attached and which carries a winding gear 53 which is joined by a train of gears 53', 54 and 55 to the gear 17' which is driven by the motor 14. Thus the spring 51 is kept wound by the motor 14, excess wind being taken care of by the frictional connection of the spring 51 with the barrel 50 before described. The barrel 5O gears into a pinion 56 on which is a gear 57 driving a pinion 58 on which is a gear 59 driving a pinion 60' on which is a gear 61 driving a gear 62 on a cam shaft 63. On said shaft are two escape arms 64 and 65 in different planes. The shaft 63 also carries a gear 66 which drives a fan fly 67 by which the speed of the shaft 63 may be regulated. Also mounted on the shaft 63 is an eccentric 68 and also an arm 69. The eccentric 68 drives a fork '10 on the lever 30 and thus gives said lever one oscillation at each revolution of the shaft 63. The arm 69 actuates a cam 71 on the lever 44.

The cam shaft 63 stands normally locked in the position shown in Fig. 1, the arm 65 being locked on an arm 72 on an anchor '73 pivoted at 75 in .the framework and having a second arm 74 adapted to lock the arm 64. The anchor 73 has a tail -'76 which is actuated by either of two stops 'tion thereby permitting the arm 65 to escape.

The cam shaft 63 turns slightly until the arm 64 is locked on the arm '74 of the anchor 73. When current is again made, the stop '78 restores the anchor 73 to its normal position, the' arm 64 escapes and the cam shaft 63 completes a revolution reciprocating the bar 28. However there is no effect on the feed wheel sincetlieidetent 38 has not been tripped and the pawl 27 does not engage the wheel 24. T; v

Again start with the partsin the position of Fig. 1 and assume the current broken and made by the switch 12, but this time make a second break of the current during the time the finger,

or arm, 69 is depressing the cam 71. The detent 38 will now be tripped, fer the action of the arm. 69 has raised the lever 43 so it will act on the tail 42. Consequently the wheel 24 will be fed one tooth and-the clock hand 23 will be advanced.

From the preceding it will be apparent that in order to advance the wheel 24, two breaks in a certain time relation will be required. A single break of the current will simply result in an idle revolution of the cam shaft 63. Further, unless the second break of the current is given, or occurs, during the time the arm 69 is engaging the cam 71, the wheel 24 will not be fed, for in this latter event the detent 38 will not be released. It is also evident that as many sets of impulses as desired may be sent in when the clock is synchronized. Each pair of, impulses will advance the wheel 24 one tooth until the zero, or blank tooth, position has been reached. Further impulses will be lost for that particular clock. The missing tooth permits bringing the clocks together when they show different times less than one hour apart. Suppose 12 synchronizing impulses sent into a group of clocks. Each clock will be stepped ahead until the hand reaches 60 (the position of the missing tooth 26) and the remainder of the impulses will be lost.

In order to reset the lever 34 the right hand end of the slot 32 acts on the pin 33 as the lever 30 is rocked to the left by the eccentric 68 which comes to rest slightly beyond its extreme right hand position. The lever 34 is thrown to a position where it is locked on the detent 38 and then the bar 28 moves slightly to the right before the cam shaft 63 is locked by the arm 65.

In order to provide for the rare case of a fast clock I have provided a cam 89 on the bar 28, this cam engages a pin 25 in the wheel 24 when said wheel is in its zero position.

In Fig. 2 I have shown an alternative magnetic arrangement in which instead of work- .ing the pull rod 49 from the leak fleld of the motor 14 I have provided a pair of magnets 79 and 80 acting on armatures 83 and 84 mounted on a lever 81 pivoted in the framework at 82. A spring 87 pulls the armature lever 81 to a stop 86 in the framework. The two magnets 79 and 80 are connected in parallel to the mains 10 and 11 and a condenser is connected to one of the magnets to split the phase and avoid chattering.

Having described the arrangement and mechanism of a single clock connected to the light and power mains and how this clock may be brought to 60 by a succession of current breaks suitably timed, I will now describe the central station arrangements and circuit connections by which the secondary clocks are arranged in a system.

Referring to Fig. 8, 90 is a generator at a power station supplying regulated alternating current to the mains 8 and 9. The generator 90 has associated with it suitable means (not shown) for regulating the frequency of the current to a source of time. See my patent above. At a second station is a second generator 91 also supplying electric energy and as is well known the two generators will keep in step with each other and supply regulated current to the mains 8 and 9. Connected to the mains 8 and 9 through relay armatures 94 and 94' is a generator 92 which generates current of a higher frequency than the 60 cycles generated by the generators 90 and 91. I have found 1000 cycles a suitable frequency for the generator 92. This generator is normally disconnected from the mains at the relay armatures 94 and 94' which are controlled by a magnet 93 which, when excited will attract its armatures and throw current from the generator 92 on the lines 8 and 9 through a transformer 133 to adjust the voltage to a suitable one. The magnet 93 is in a local circuit containing a battery 95 and a contact 96 adapted to be actuated from teeth of a transmitter disc 97. This disc is made of insulating material and has 12 sets of teeth 98 on its circumference, the teeth 98 occurring in sets of two. The disc 97 is driven through a pinion 100 by a gear99 which is driven by a barrel or drum 103 from which is suspended a weight 104. Suitable winding arrangements for the weight are provided. The'gear 99 drives a gear and pinion 101 which drives a fan fly 102 serving to regulate the speed of the disc 97. and thereby the speed at which the contact 96 is closed.

The disc 97 is normally locked from turning by an arm 105 locked on a detent 106 held by a spring 107 to a stop 108. The detent 106 is pivoted at 109 and carries an armature 110 acted on by a release magnet 111. The time of revolution of the disc 97 and the spacing of the teeth 98 is such that there is an interval of about one half second between the teeth of the same pair and about two seconds between pairs. If the re lease magnet 111 is excited, the arm 105 will be free from the detent 106 and the disc 97 will make one revolution resulting 12 pairs of currents in the relay 93 which will send 12 pairs of currents from the generator 92 on the lines 8 and 9. The

release magnet 111 is operated from a master' clock 112 as shown diagrammatically in Fig. 6,

the master clock 112 closes the circuit of the release magnet 111 which includes a local battery 113, once each day at some suitable time, preferused forms no part of my present invention. By

the time thedisc 97 hasmade one revolution, after being started by action of the magnet 111, the circuit of magnet'lll has been opened by the master clock 112 and the arm 105 is locked on the detent 106 until the next synchronizing period.

Connected to the line wires 8 and 9 is a typical light, power and clock installation consisting of a transformer 114 having a primary coil 116 and a secondary coil from which line wires 10 and 11 extend through normally closed relay contacts 120 and 121 to lamps 129 and secondary clocks 88, the latter being of the construction described in detail in Fig. 1. The contacts 120 and 121 have a like function with the switch 12 and are controlled by relay armatures 122 and 123 held by springs 124 and 125 to keep the contacts closed. A magnet 128 serves to actuate the armatures 122 and 123 in a manner hereinafter to be described. Connected between the transformer 114 and the contacts'l'20-121, to the line wires 1o-11 is a motor 119 and a detector 130 whose function is to detect "and amplify (if necessary) the 1000 cycle current from the generator 92 when the same is put on the line at the synchronizing period. This detector is the same as is used in systems of so called wired radio. It consists of a circuit resonant with the current of 1000 cycles and a detector of the triode type to rectify the current and send it through the relay 128 and actuate the latter. An amplifier may be used if necessary to raise the detected 1000 cycle current to a power level to energize the relay 128.

From the preceding it is apparent that the relay 128 will open the circuit of the secondary clocks 88 in response to currents made by revolutions of the disc 97. This will result in advancing the clocks 88 to 60 thereby synchronizing them. It may be that the impedance of the transformer 114 is such that it will not let enough of the 1000 cycle current through to operate the detector 130. In this event condensers of small capacity 117 and 118 may bridge the transformer windings as shown. On account of the small capacity they will be practically opaque to the 60 cycle current while they will readily transmit the 1000 cycle current used for the synchronizing current.

It may be asked why it isdesirable to go to the trouble of sending the 1000 cycle current on the line to break the current at the substations for synchronization purposes, why not break the current at the central station and omit the 1000 cycle trimmings? The answer is that in a large system it is undesirable to break the line current. besides the. transient .disturbancesset up in the system there is the problem of the partial stoppage of large motors such as is shown at 132 connected to the lines 8'-9 by the transformer 131, there-lathe throwing out of circuit breakers and other, protective devices and further the problem of the line wires being supplied from two or more power stations with the consequent difllculty of breaking all sources of supply simultaneously and reconnecting them again in phase. From these considerations I prefer. to split up the system into units which may-not be inconveniencedby-the ience.

the line 8-9- briefhinterruptions of current required to synchronize, send a'characteristic current on the lines and to transform this current intoa breakin the various groups. By this expedientit is possible to localize the clocks in a group which may. have the current broken without inconven- It is of coursepossible that the yst m may be small enough that the line current may be broken at 1 the central-station. In this event the relay 128 and its contacts would replacethe m net ..;93. Lconsiderthis arrangement wi h n the s ope of invention.gsince ,with the contacts 120121 breaking lthe connection of the generator 90 to I one is simplydupllcating the arrsnsement at the substation. 1 I a .While I have the synchronizing currents;

or -ether the succession ofthem sumcient to. ad-

vancethe secondary clocks 88 an hour, this is y az r d ar n emen -1111a mo o clo k the chief cause of a clock's being slow is a current outage. the clockruns it must go in step get out, they get outmore self running clocks and requires. correspondingly greater correction; I wish to point out that the synchronizing ar-- 7' rangement may be duplicated onthe second. hand oflthe clock in the'event itis desired to set the c nd band also, V

bs or o ed nref r m th speed oi the transmitter disc 97 such that it willsendout a pair of currents each two seconds. This will require 24 seconds for a full revolution of the disc which should therefore be started by the master clock 24 seconds before the hour so that the last current will be sent just on the hour.

daryclocks from a break in the power current of great advantage, it avoids providing an extra con,- ductor for synchronizationpurposes and permits the clocks to bothbe run and synchronized over existing light wires. Further the plan of synchronizing from a plurality of breaks in a time relation avoids false synchronization from accidental line disturbances.

While I have shown my system as run from existing power system, it may be used to great advantage in the field now filled by minute jumper clocks. The herein described clocks may be attached to theexisting light circuit (assuming that to be supplied with regulated alternating current) and amanual switch 12 shown in Fig. 1 used to reset the clocks after an outage of current. a It is not necessary to have the master clock and transmitter equipment. Onemay listen to the Arling-- ton time signals and manipulate the switch 12 ac- I cordingly to correct for the infrequent times an outageoccurs.

While I have shown my invention as applied to clocks in which the time indicating means are I consider the plan of the seconhands and means responsive to a plurality only of i breaks in said current to determine when said secand. means shall become efiective on said hands. 2. In an electric clock system the combination hands, a synchronous motor run from said current to move said hands, a second means to move said,

of a source of regulated alternating current, clock hands, a synchronous motor run from said current -to move said hands, a second means of moving said hands and means responsive only to a succession of breaks in timed relation in said current to determine when said second means shall act on said hands.

3. Inan electric clock system the combination of a. central station, a substation, line wires connecting the two, meansto impress a regulated alternating current of a certain frequency on said Iline wires, a secondary clock at said substation,

' a hand for said clock, a synchronous motor driven :by said current to move said hand, means to impress current of a second frequency on said wires, a second means operated by a break in said regulated current to' move said hands, a detector for said current of a second frequency at said substationand means governed by said detector to break the regulated current whereby said second means operates said hand.

4.In an electric clock system the combination of a central station, line wires, means to impress an alternating current of a certain frequency on said wires, means to impress a currentof a second frequency on said wires said currents being capable of simultaneous existence on said wires, a transmitter determining that said second current shall be impressed on said wires in a succession of impulses having a timed relation, a lock for said transmitter and means to release said lock.

5. In an electric clock the combination of a source of regulated current, clock hands, a synchronous motor run from said current to move said hands, a second means to move saidclock hands and means brought into action by a break in said current to determine that a second succeeding break in said current shall render said second means effective on said hands.

6. Inan electric clock the combination of a source of regulated current, clock hands, a synchronous motor to advance said hands and run 3 from said current, a second means of advancing said hands and means responsive to a break in said current to determine that a second break in said current shall render said second means eiIective to advance said hands.

7. In a clock' system the combination of a source of regulated current, a clock hand, a synchronous motor run from said current and adapted to move said hand, a second means to move said hand, said second means being operated by successive breaks in timed relation in said current and meansto render said second means inoperative to move said hand when said hand has reached a certain point.

, ARTHUR F. POOLE. 

